Little did “The Rock” know, but his simple yet thoughtful gesture years ago had a tremendous effect on a man and his late father.

Dwayne Johnson recently shared a photo on his social media accounts of himself, posing with Officer Richard Arias while filming his HBO series “Ballers.”

In the post, he explained that the officer had told him about an encounter the two had at a hospital, back in 2008. At the time, Johnson’s mother, Ata, was battling lung cancer, and Arias’ father, Jesus, was as well. The Rock had smiled and held the door open for Jesus—an act that spoke volumes to the man.

“‘You have no idea what that moment meant to him. And me,'” the Rock wrote, recalling what Arias said to him.

According to the post, the actor was approached by his security, who told him about officers who wanted to meet him—including one who had a personal story to share. After taking photos with them, the Rock spoke with Arias and discovered that he and the officer were taking their parents to weekly treatments at the same time. Though, sadly, Jesus died last year, and it’d been years since the incident, Arias had meaning to address it.